The third virtual event in the series Wine Behind the Curtain built upon the content of the previous two episodes introducing wine and terroir, explaining how the winemaker’s process affects the quality of wine. This event was moderated by Holly Goodson, a biochemist in the Department of Chemistry and Biochemistry at the University of Notre Dame. Goodson was joined by Andrew Waterhouse ’77, the Director of the Robert Mondavi Institute for Wine & Food Science at UC Davis and Co-Editor in Chief of the Journal of the Science of Food and Agriculture and Chris Kajani, Head Winemaker and General Manager at Bouchaine Vineyards. This discussion began with a basic introduction to the key winemaking decisions that impact wine qualities. The session concluded with an opportunity for the speakers to answer some questions from viewers.
As always, the speakers sipped on glasses of wine as they dove into a fireside chat discussing the winemaking process. Waterhouse began by describing the process of harvesting, cleaning, destemming, and crushing the grapes. Then, the grapes are fermented, typically relying on yeast, for up to several weeks depending on the temperature, warm for red and cool for white. The seeds and skins are removed to clarify the liquid and left to rest so the yeast can settle. After the aging period (lasting months to years), wine is bottled and sent to distributors.
Winemakers must work in close proximity with vineyard managers to understand and respond to the needs of the property and grape-growing environment, particularly as temperatures and climate change. A deep familiarity with the vineyard site takes time and dedication, but can make all the difference in the quality and timeliness of a grape’s harvest. Winemakers and vineyard managers also must work around commercial constraints such as storage, fermentation, and aging capacities, the availability of laborers and energy and budget limitations. Kajani reported – from her barrel room no less – that her winery conducts night harvests to allow more flexibility in the case of broken machinery or unavailable laborers, given the nearly 24-hour hands-on harvesting process, as Waterhouse had previously described.
While there is machinery for destemming and other steps of the winemaking process, winemakers take care to oversee and contribute to all elements of the process to ensure the wine is not ruined through human or machine error. Winemakers also taste (and spit) every wine each day (sometimes fifty barrels or more) to track their progress and make critical decisions about the wine’s flavor. This requires a taster to be sharp, skilled and experienced. While tasting grapes and wines every day may sound like a dream to most wine lovers, Waterhouse and Kajani note that there are great challenges to the process of staying vigilant as a taster in charge of the wine’s final flavor.
Temperature controlled by Mother Nature affects grape growth, water retention, and potential sun damage; however, artificial or human-controlled temperature plays an equally important role in the fermentation process. Temperature is the greatest control a winemaker can use to manipulate the taste of wine and speed of fermentation, and it can make drastic differences in the final product. Destemming decisions made by winemakers also impact the phenolic character and amount of tannins – which contain the antioxidants within a wine – within a bottle, as well as the flavor profile of both red and white wine. The tank a winemaker chooses to ferment and/or age wine in also impacts the taste of the wine, whether it is a 60-gallon oak barrel or a 1000-gallon stainless steel tub. The choices of a winemaker are endless, and all are important in shaping the final product.
To conclude the event, both speakers answered a few final questions about corks, innovative efforts in bottling, and the more enjoyable aspects of winemaking as a career. A rewarding aspect of the work that Waterhouse and Kajani both vouch for is the community around winemakers in a particular region who are willing to share expertise, lend mechanical equipment when needed and relate to challenges in a season’s harvest.
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